1. Field of the Invention
The present invention relates to a pipe joint for coupling piping.
2. Prior Art
An example of a conventional pipe point is shown in FIG. 7.
As shown in the drawing, this joint has, in its cylindrical main body 1 with a male threaded portion at one end, a slender cylinder 2 slidably and coaxially installed, and a holding cylinder 3 placed between the slender slidable cylinder 2 and the main body 1 in the way to slide freely to and fro, and the gripping force by the slidable cylinder 2 and the holding cylinder 3 secures a pipe inserted between them in a non-detachable manner.
The main body 1, as shown in the drawing, has a pipe insertion port 10 at the other end, and a taper 11 narrowing toward the opening port provided in the inner circumference near this pipe insertion port 10.
The holing cylinder 3 is made of elastic material and has a slit 30 opening toward the pipe insertion port 10 in its circumferential wall, and, as shown in the drawing, its outside diameter is slightly larger than the diameter of the pipe insertion port 10.
The space between the holding cylinder 3 and the slidable cylinder 2 is set slightly smaller than the wall thickness of a pipe to be connected to them.
Therefore, when a pipe is inserted forcibly into the space between the holding cylinder 3 and the slidable cylinder 2 through the pipe insertion port 10 and then pulled back, the holding cylinder 3 and the slidable cylinder 2 are to move toward the pipe insertion port together with the pipe. From the moment that the holding cylinder 3 abuts against the taper 11, the pressing force by the taper 11 acts on the holding cylinder 3 in a direction of reducing its diameter. In consequence, the gripping force on the pipe by the holding cylinder 3 and the slidable cylinder 2 increases, thereby the pipe being secured in a locked state.
As aforementioned, in this type of pipe joint, easy and convenient connection is conducted only by inserting a pipe through the piping insertion port 10 and then pulling it back.
However, this pipe joint has a disadvantage that the once connected pipe cannot be detached therefrom.